Process of making phenol aldehyde condensation products



I Patented May 26, 1931] v UNITED. STATES NT (OFFICE Arr-ensos'masn'rzna, or nosmnnunune, AND rmz mmm, or vmmwn,

nusram, assrcnons 'ro remorse LIMITED, or no'rrmenul, momma, aconrnnvornnemnn g raocass or MAKING rnmmnawnmn commusarron rnonuors msnnwai Application filed Kai-ch 20, 1923 serial no. 268,206, in Austria 1m 0, m7.

, The oily or resinous precipitates which are formed when phenols act onaldehydes in the presence of condensing agents of a' basic or acidnature, always conta n a portion of 4; the raw materials which do notenter into reaction and other substances which are taken up from theoriginall added solution, which unfavourably afiect t e product to anextraordinary degree. the condensation products in a pure form has ledto a large number of suggestions, all

of which aim at freeing the oily or. resinousdistributedin thecondensation solution, so that in the formation, state there is acolloidal emulsion. This emulsion has however very little stability. Thep combine together very quic ly to form a coherent precipitate withadsorption of a portion of the substances contained in the solution andwith the occlusion of some of the vehicle. There is formed in this wayan irreversible colloidal precipitate which set.- tles as an oily orresinous hase tothe bottom of the vessel and retains the adsorbedsubstances with rest persistency. A portion of the vehicle an of thesubstances contained therein become occluded in'th'e greater and lessercapillaries of the resinous mass. Also on the further solidification ofthe resin precipitate which takes place the adsorbed substances are onlygiven up againwith difficulty owing to the small total surface of theseparated resin. It is true that by suitable measures the greatest partof the solvent mechanically held in the capillaries can be removed buton the other hand the substances adsorbed by the coarsely aggregatedparticles The endeavour to obtain ing to the present invention, dis

at the moment of its formation is colloidally articles of resin of resinby colloidal chemical superficial forces can only be'extracted a ainwith difficulty and only artially. 'f an attempt be made to disso v'efthe precipitated resin again and reprecipitate it, a portion of theadsorbed substances will remain in solution it is true, butanother'portion is'again' adsorbed on precipitation and occluded in themass. Purification in this way is therefore only possible with greatdifiiculty, apart from the fact that the repeated solution and"precipitation would alter the character of the resin. Also treatment ofthe condensation j products with hydrotro icsalts and precipitation withacids can a we s only remove a portion of the adsorbed su originalresin.The experiments instituted fore to the following results: If, asaccordrsively acting substances (protective collo ds) be added to thestarting solution before ,or at the moment of the condensation reactionand the solution dilutedto such an extent that the ances and this methodalso brings with ita change in the have led therei 7 resin cannotseparate out in the form of acoherent mass, then the "character of theprecipitate will be fundamentally modified and a resin will be obtainedwhich, owing T to its itself 1n the condensation solution, so to speakto a self-purification. Whereas in all methods which have been knownhitherto the resin separates immediately after its formation asajcoherent phase in'theform of an oily or resinous precipitate from thefluid phase, the primarl culiar form of subdivision subjects y formedmulsion col-- loid in the. method according to the present invention isstabilized by the dpresence of the protective colloids. Regarde' from. apurely phenomenological "point of view, what hap-,

to the present invention is ereasin the methods hitherto pens accordinas follows: employed an oily or resinous deposit vcr quickly collects atthe bottom of the vesse there is formed with the new method in thepreviously clear liquid a finely divided separation consisting. of smalldrops, so that the liquid assumes a milky character. If now the processbe continued for a sufiiciently long I which are easily or diificultlysoluble, or insoluble, in alcohol.

.In some cases, particularly when an excess of formaldehyde is used, aproper precipitation does not take place in the original so ution butonly an opalescence. On pourin the mixture into water or dilute acid averulent cake is then formed which can easily broken up.

Thus essentially the process according to the present invention consiststherein that in order to produce a pulverulent precipitate I of thecondensation product, the condensation is carried out in the presence ofdispersively acting substances (p:otective colloids) at such a dilutionthat the resin can not separate soout in the form of a coherent mass.The degree of the dilution which is necessary for the separation of theresin in a owdery form can be determined in each con ensation solution.A colloidally dissolved. body separates out of solution at a certaindilution, as a coherent phase whilst above this dilution it separatesout in the form of a powder. This fact, which is in accord withgenerally accepted theories of colloid chemistry, is made use of in theprocess of the present invention. The degree of dilution necessary underthe prevailing conditions, in order to cause separation of the resin asa powder, is first of all determined experimentally and then thesolution is diluted accordingly. On heatin this diluted solution theresin is precipitate in the form of a powder and the added protectivecolloids prevent the separate small particles of this powder fromcombining together to form larger particles. The stabi 'zation effect ofprotective colloids in dilute solutions is also a well known colloidalchemical phenomenon. Both the degree of dilution necessary and theeffectiveness of the rotective colloids are, as is known in colloidchemistr mainly dependent on the temperature of t e condensationsolution, the nature and the quantity of the added materials, theion-concentration and the like.

It has further been found that it is of great advantage in the processof the present invention to carry out the condensation with the help ofbasic condensing agents. In addition it has been shown that advantageousefiects are obtained when small quantities of neutral salts are added tothe condensation solution before the separation of the pulverulentresin.

It has been proposed to add salts of sulphoacids which act asemulsifying a ents and it has also been proposed to add al uminousmaterials in the condensation of phenols with aldehydes. These knownprocesses however, are not conducted at the dilution at which a powderyprecipitate of the condensation product is obtained and the addedcolloidal bodies apparently do not act as stabilizationefiecting orprotective colloids.

The stabilizing action of the added protective colloids and theretarded, aggregation secured .thereby is of quite extraordinaryimportance for the manufacture of the resin, irrespective of whether theprimary colloidal emulsion is retained as such by the ad'- dition of theprotective colloids or whether an aggregation takes place first in asmallmeasure and the protective action only makes itself manifest aftera fixed stage of aggre-' gation has been attained, bypreserving theparticles from further coarsening. In each case the further processtakes place in a more or less dispersed system, in which the solidphase, that is to say the'resin particles, de-' velop a large externalsurface as against the liquid phase, without however having thepossibility, in consequence of the protective colloids added, ofcoalescing into large masses. The separate resin particles willtherefore solidify in the course of the heating, and the activeadsorption coefficient of the separate particles of resin for thesubstances contained in the solution disappears gradually at the sametime. That after coagulation or solidification of a colloidalprecipitation the adsorption falls off is a well known colloidalchemical fact. If for example colloidal mercury sulphide be caused tocoagulate by a dyestutf, this dyestuff will be first adsorbed by theprecipitated colloid. After (precipitation has taken place it will benotice how the dyestufi gradually emerges into the surrounding solutionand the solution becomes more and morestrongly coloured. In like mannerin the present casein proportion as the individual particles of resinsolidify, the more will the substances adsorbed by them be thrown offinto the solvent surrounding them. The results of this falling off ofthe adsorption will naturally only appear to be effective in practice solong 1 ao-acct formed resin is precipitated at once in a closed phase.The solidification of the resin takes place within compact masses, inwhich the falling off of the adsorption owin to the small sur ace nolonger acts fully an which are therefore alsono longer so easilyaccessible to washing.

As protective colloids we may use for example gum arabic, saponin,tragacanth, dextrine, gelatine, or other substances which act asprotective colloids.

The powders obtained-are practicall free from all impurities and can bekept or an indefinitive period without changing. Some are perfectlysoluble in alcohol and alkalies and can be used for the manufacture ofvarv nishes or the like in the usual way. The owders which aredifiicultly soluble or inso uble in alcohol may be used in the arts,similarly to the known resin-like masses of the same kind.

4 To carry out the new process we proceed, for example, as follows:

(1) 100 kg. meta cresol mixture and 110 kg. formaldehyde 30% by weightare mixed with 190 litres of distilled wateri'n which 2 -kg. of gumarabic have been dissolved, and heated to boilin As soon as thetemperature of the solution has risen to 80 C. litres of double no'rmalcaustic soda solution are added, after which the reaction becomesexothermic and the solution boils up strongly. In a few minutes thefinely divided oil condensation product separates out, and

this can be boiled now as long as desired and is thereby convertedgradually into a fine pulverulent form. It is now run. ofi into a woodencask, in -which the liuid is separated acioh A powder of a sand-likecharacteris formed which is filtered ed and ireed from the motherliquor.

The product obtained is of a light yellow or light brownish colour. a100 kg. amt, carbolic acid are-boiled under a reflux condenser with nokg. formaldehyde 80% by 'weiiz t and 150 litres of 25% common saltsolution in which 2% kg. of gum arabic are dissolved an 50 litres ofdouble normal caustic soda solution 25 litres of doubie normal ammoniu.

The separation of a milkycondensation prod not soon takes place- Thereaction is continued. until a send-like precipitation takes place inthe hot liquid itself or on the addi-= tion of water or acid solution toa sample taken therefrom. After this the procedure water or dilute hydewhic cipitated condensation product becomes insoluble in alcohol andalkali solutions or swells only 1n these liquids without dissolv- 111gcompletely.

(5) 500 kg. cryst carbolic acid are heated a solution of 1 kg. gumarabic,'in 300 kg. formaldehyde 30% and 50 kg. double normal causticsoda solution. In this case the condensation product formed remalnscolloidally dissolved. After boihng for about one hour a precipltate isformed on a sample beingtaken and poured into a dilute to boiling inacid solution. As'soon as this moment comes the mass is allowed to runinto the corresponding quantity of diluted sulphuric acid and theprecipitate formed filtered off and washed. If the formaldehyde bereplaced by other aldehydes, such for example as acetaldehyde, furfural,acrolein, and the like, products of an analogous nature are obtained.

We claim:

1. In making a resinous condensation product of a phenol and analdehyde, the herein 1 described improvement which comprises reactingsaid materials together in the presence of a basic condensing agent andin the simultaneous presence of a protective colloid.

2. In the process of making a resinous condensation product of a phenoland an aldehyde, the herein described improvement which comprisesheating a phenol and a reactive aldehyde in the presence of a condensmgagent, until the condensation reaction ta es place, and adding aprotective colloid at a stage not later than such reaction beingefiected, and keepin the mass hot to allow any unreacted heno andaldehyde to be dissolved out of t e reaction mass, while the latter isin a finely divided condition.

3. Aproc for making a resinous condensation product of a phenol and analdetures. A

ALFONS OSTERSETZER. a t NZ BIESENFELZ).

we afiix our signais as in Example 1. The powderohtained is also of aslightly yellow colour.

(3) By replacing the gum arahie solution used in Examples 1 and 2 by asuitable solu= tion of saponin, casein, atine, tragecanth and the like,quite silar results are oh-= tained. a

(4;) 0n any of the alcove p being eontinued for twehours the powdery precomprises heating a phenol and a reactive aldehyde in-the presence ofconaae

